I have a small engine driven generator that I am trying to build an AVR for. It is an 1800 RPM alternator with two slip-rings, 5 KW, 120/240 volt single phase unit driven by a 4 cylinder engine. This unit was built in the fifties and everything checks out but it is missing the voltage regulator and exciter system. I can buy the adjustable voltage regulator and static exciter but I would like to build one.
Does anyone know of a good, detailed reference manual or have suggestions where to start.
Thank You

 

This is the circuit of a 240V AC generator AVR. I had to repair it so i reverse engineered it.

 

Fortunately I had asked the question a couple of years ago, and fortunately I remembered the secret code. An "AVR" is an Automatic Voltage Regulator, for those folks who might be as confused as I had been.
Why hide the topic of a request for assistance behind a BIT OF JUNK JARGON???
For the operation, I am guessing that the 90 volts yellow pair, and the 25 volts blue and brown pair wires each are fed by additional windings on the generator field winding core. The 90 volts gets rectified to power the rotating field thru the slip rings, and the 25 volts serves as the feedback signal.
As the feedback voltage rises, the zener diode starts to conduct, increasing the base bias on the 2N5551 PNP transistor, causing it to draw more collector current and thus reducing the gate bias on the mosfet, so that it in turn reduces the current thru the rotating field winding.
This seems like a fairly solid control scheme, if those sorts of voltages are available either directly from auxiliary windings, or by means of a transformer fed by the main output winding.
My thanks to "Debe" for a well drawn answer!!

 

Hi Bill. You are quite right on how it works, the voltages come from seperate windings on the stator. Actualy in the world of generators AVR is not junk jargon. If you go to Ebay & put Generator AVR there will be a lot of them to choose from. At the price they are its not realy worth building one.

 

This is the reg that i got the circuit from. After working on a few diferent AVRs of this type the circuit seems to be very similar.

 

This was the failure in another one, was dry joints on the MOSFET & easily repaired.

 

Certainly poor soldering and high vibration will combine to produce failures.

 

This is the circuit of a 240V AC generator AVR. I had to repair it so i reverse engineered it.View attachment 332002

This is the circuit of a 240V AC generator AVR. I had to repair it so i reverse engineered it.View attachment 332002

Thank you very much! I feel that with little bit of studying I will be able to build the AVR. Thanks Again.

 

Isn't an "Automatic" Voltage Regulator kinda like a "Hot" Water-Heater ?,
or maybe a "High-Voltage" Tesla-Coil ?
.
.
.

 

What is wrong with using acronyms associated with the subject they are used within?

The op already defined the context as a generator subject.

If you don't recognise it, you likely know nothing about it, or your memory is not as good as you thought it was.

Maybe try a little test?
These all have well known meanings within specific subject areas.
Can you recognise them?

AVR
AGC
AFC
BBC
DVM
DMM
ECG
FET
GDP
HTL
Hfe
MCB
MOSFET
NOP
NPN
OOP
PNP
QRS
R&R
SOS
TTL
UVA
VBA
WWW
XXL
YYD
Zzz

Absolutely nothing wrong with using them in a stated context.

 

It's the "specific-subject-areas" part that becomes the problem for me.
Electronics is just a hobby for me, so I don't place as much significance on it.

I try not to commit too much memory to acronyms because I switch subjects ~5 or ~6 times a day,
and much of that is "speed-reading" or scanning headlines, or listening to Podcast-Videos at 1.75X speed.

Plus, it's always been an observation of mine that people who like to use a lot of acronyms do so
in an attempt to create the impression that they know more about the subject than they really do.

Most acronyms don't really "save" all that much time and effort in typing, or writing,
but they do create stumbling-blocks for people new to the subject,
and while the subject matter of Voltage-Regulators is certainly not new to me,
some trades, or specialized areas of a particular subject, ( such as old Generators ),
may hold on to acronyms that were created more than ~100-years-ago,
but don't fit quite as universally in present time,
or they may not be used in similar areas anymore, such as modern Solid-State-Electronics.
.
.
.

 

L.Q.C. is so very totally CORRECT!! It is sometimes rather frustrating to read a technical article in which the author uses a lot of rather obscure acronyms familiar only to a very narrow niche.
Unlike LQC, though, I AM an engineering professional, now semi-retired, but refusing to "vegetate." Still active in service and consulting.
Of course it is easy for one immersed in a narrow field to not see that others not so deeply immersed might read that article or posting.
The first acronym that "got" me on this site was "MCB", a lazy reference to the smaller (Miniature) branch circuit breakers in a distribution panel, rather than the more common reference to "Main Circuit Breaker", used elsewhere.
So unless one is entering text on an older 12-key cell phone, it makes sense to spell out a term at least initially.

 

What is wrong with using acronyms associated with the subject they are used within?

The op already defined the context as a generator subject.

If you don't recognise it, you likely know nothing about it, or your memory is not as good as you thought it was.

Maybe try a little test?
These all have well known meanings within specific subject areas.
Can you recognise them?

AVR
AGC
AFC
BBC
DVM
DMM
ECG
FET
GDP
HTL
Hfe
MCB
MOSFET
NOP
NPN
OOP
PNP
QRS
R&R
SOS
TTL
UVA
VBA
WWW
XXL
YYD
Zzz

Absolutely nothing wrong with using them in a stated context.

DVM is a Doctor of Veterinary Medicine isn't it?

 

DVM is a Doctor of Veterinary Medicine isn't it?

If you are talking in a animal, medical context, it may very well be. (I haven't googled it) .

Have you read all the posts or just skimmed through?

 

Even when the acronym is known to the reader,
there can still be ~5 different ways that a manufacturer could have implemented a "standard" method.
.
.
.

 

Consider that not that many folks available to provide wisdom and answers on this site are in the power generator business, and that they still have a good deal of insight as to how circuits work, it would be a handy courtesy to spell out the whole subject name for the title. That quite small bit of effort could reap some benefits.
There is a great deal of feedback system insight that could apply to making a generator setup perform very well.

 

BBC??? Don't even go there....

 

What is wrong with using acronyms associated with the subject they are used within?

The op already defined the context as a generator subject.

If you don't recognise it, you likely know nothing about it, or your memory is not as good as you thought it was.

Maybe try a little test?
These all have well known meanings within specific subject areas.
Can you recognise them?

AVR
AGC
AFC
BBC
DVM
DMM
ECG
FET
GDP
HTL
Hfe
MCB
MOSFET
NOP
NPN
OOP
PNP
QRS
R&R
SOS
TTL
UVA
VBA
WWW
XXL
YYD
Zzz

Absolutely nothing wrong with using them in a stated context.

Sometimes you have to get deeper in context to sort it out: is a VFD a vacuum fluorescent display, or a variable frequency drive. Could the VFD possibly have a VFD to show its operation mode?

 

BBC ???
Nahhh,
LT-1, but from what decade ???

Hint ....... GDI all the way !!!,
and boosted twice by Borg-EFRs, with custom 1,200 PSI H2O/Meth-Injection.
14:1 C/R on Regular-Gas and ~38-MPG, ~1,400 HP/ 1,250 TQ @ 7,500 Rs ........
.
.
.

 

BBC ???
Nahhh,
LT-1, but from what decade ???

Hint ....... GDI all the way !!!,
and boosted twice by Borg-EFRs, with custom 1,200 PSI H2O/Meth-Injection.
14:1 C/R on Regular-Gas and ~38-MPG, ~1,400 HP/ 1,250 TQ @ 7,500 Rs ........
.
.
.

Is that your "funny Car" engine specification??